Investigation on flavonoid composition and anti free radical potential of Sida cordata

Sida cordata, a member of Family Malvaceae is used in folk medicine for various ailments including liver diseases. In this study we investigated, its flavonoid constituents, in vitro antioxidant potential against different free radicals and hepatoprotection against carbon tetrachloride (CCl₄)-induced liver damage in rat.

Dried powder of S. cordata whole plant was extracted with methanol and the resultant (SCME) obtained was fractionated with escalating polarity to obtain n-hexane fraction (SCHE), ethyl acetate fraction (SCEE), n-butanol fraction (SCBE) and the remaining soluble portion as aqueous fraction (SCAE). Diverse in vitro antioxidants assays such as DPPH, H₂O₂, •OH, ABTS, β-carotene bleaching assay, superoxide radical, lipid peroxidation, reducing power, and total antioxidant capacity were studied to assess scavenging potential of methanol extract and its derived fractions. On account of marked scavenging activity SCEE was selected to investigate the hepatoprotective potential against CCl₄ induced toxicity in Sprague–Dawley male rats by assessing the level of serum markers (alkaline phosphatase, alanine transaminase, aspartate transaminase, lactate dehydrogenase, bilirubin, and γ-glutamyltransferase) and of liver antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), glutathione-S-transfers (GST), glutathione reductase (GSR), glutathione peroxidase (GSH-Px), and reduced glutathione (GSH) and lipid peroxidation (TBARS). Histology of the liver was performed to study alteration in histoarchitecture. Existence of active flavonoids was established by thin layer chromatographic studies.

Considerable amount of flavonoid and phenolic contents were recorded in the methanol extract and its derived fractions. Although the extract and all its derived fractions exhibited good antioxidant activities however, the most distinguished scavenging potential was observed for SCEE. Treatment of SCEE decreased the elevated level of serum marker enzymes induced with CCl₄ administration whereas increased the activity of hepatic antioxidant enzymes (CAT, SOD, POD, GST, GSR and GSH-Px). Hepatic concentration of GSH was increased while lipid peroxidation was decreased with SCEE administration in CCl₄ intoxicated rats. Presence of apigenin with some unknown compounds was observed in SCEE by using thin layer chromatography.